“I always encourage people to understand there’s a difference between being transparent about what CBO does and scientific replicability. They’re never going to get that,” Holtz-Eakin explained.

“CBO has lots and lots of proprietary data,” he said, offering a reason why the CBO’s books are not fully open to outside observers.

“When I was there we got data from some of the pharmaceutical companies and we signed confidentiality agreements in order to get it,” Holtz-Eakin continued. “We needed to do a good job on the prescription drug bill but we could not have shown that to anybody, including Congress. Any time Congress has ever made noise about trying to reach into CBO in that way, I’ve just gone to the leadership and explained if they do it, I’m not going to get the data I need for CBO to do it’s job. It endangers the capacity of the office.”

The CBO transparency bill would require the agency to publish its methodologies and data for public scrutiny. Under current policy, the CBO relies on its Panel of Economic Advisers and Panel of Economic Health Advisers, groups of experts with relevant expertise, for guidance.

“Although CBO draws upon a diverse set of outside experts, the agency’s findings are based on its own judgments, and it is solely responsible for the substance and presentation of those findings,” says the CBO’s website.

“There are lots of technical working papers on the site which describe the development of the current methods or models,” Holtz-Eakin said. “We build special statistical models for analyzing the taxpayer risk associated with things like pension benefit guarantee corporation, student loans, housing guarantees with the FHA. There’s both from a cost estimate, description of it — also there are a lot of other materials describing the sort of infrastructure. And then, in some cases there is a boards of advisers, like forecasts, there’s a panel of economic advisers, there’s a health care panel of advisers.”

“So there are ways to get scrutiny of the methods that are used,” he added.

Some estimates the CBO is asked to make cover touchy territory and make tough judgment calls.

“I had a bill where they were going to double the pay for anyone who died, double the death benefits for anyone who died in Iraq, and we had to price that prior the invasion,” said Holtz-Eakin. “That means we had to forecast the number of casualties in Iraq. And I promise you, I don’t know how we did that. So we did our best. But the point is there is judgment. … So, I respect CBO’s efforts to explain what they do. But in the end, they are an expert body advising the Congress, and they are going to have some unique features.”